As a liposome preparation containing tacrolimus, for example, there have been known those prepared by incorporating a stabilizer such as cholesterol into phospholipid as a principal ingredient for forming liposome (WO93/08802). With such a constitution, it becomes possible to prepare a liquid preparation from tacrolimus, which is slightly soluble in water. Even if such a preparation is contacted with a body fluid, crystallization of an active ingredient does not yield so that the preparation exhibits excellent bioavailability and is stable. Therefore, the preparation can take any dosage form represented by injection, instillation into eye, nasal administration, inhalation, percutaneous absorbent, topical injection and the like. Furthermore, it also becomes possible to enhance intensive transmigration of tacrolimus to a site where transmigration of tacrolimus is particularly desired, and to suppress its transmigration to a site where transmigration is not necessarily desired. It is known that excellent effects in practice, such as enhancement of drug efficacy, reduction of side effects and persistence of drug efficacy are obtained as a result.
The liposome preparation exhibits an excellent effect to treatment of cerebral ischemic diseases such as cerebral infarction. However, since a liposome membrane is too stable, the liposome preparation tend to exhibit insufficient rapid action, like an anticoagulant, a fibrinolytic agent and a cerebrovascular dilator used as a medical treatment to cerebral infarction. Therefore, it has been required to develop a drug having an excellent rapid action capable of coping with an emergent situation such as cerebral infarction and also having an excellent redispersion property.
An object of the present invention is to improve the problems described above, thereby to provide a liposome preparation having excellent rapid action and excellent redispersion into an aqueous medium.